Deployment and lifecycle management for Nix
client: direct activation if username matches running user
+156
-7
+41
-6
apps/sower_client/lib/sower_client/activator.ex
+41
-6
apps/sower_client/lib/sower_client/activator.ex
···
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Supports two activation methods:
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- Socket mode: Communicates with sower-activator daemon via Unix socket
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- CLI mode: Invokes sower-activator binary directly (with sudo)
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- CLI mode: Invokes sower-activator binary directly (with sudo for NixOS)
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The `activate/3` function automatically tries socket first, then falls back to CLI.
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## Activation Path Selection
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The `activate/3` function selects the activation method based on type and context:
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1. For **home-manager** with username tag matching the current user:
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Uses CLI activation directly (no sudo, no socket) - enables self-managed
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home-manager configurations without requiring a privileged daemon.
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2. For **NixOS** or other types:
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Uses socket activation when available, falls back to CLI with sudo.
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3. For **home-manager** with mismatched username:
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Uses socket activation when available, otherwise returns `{:error, :username_mismatch}`.
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"""
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use TypedStruct
···
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"""
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def activate(type, path, opts \\ []) do
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socket_path = Keyword.get(opts, :socket_path, @default_socket_path)
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tags = Keyword.get(opts, :tags, [])
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if socket_available?(socket_path) do
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activate_via_socket(type, path, opts)
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else
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Logger.debug("Socket not available, falling back to CLI activation")
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if type == "home-manager" and username_matches_current_user?(tags) do
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Logger.debug("Home-manager username matches current user, using direct CLI activation")
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activate_via_cli(type, path, opts)
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else
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if socket_available?(socket_path) do
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activate_via_socket(type, path, opts)
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else
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Logger.debug("Socket not available, falling back to CLI activation")
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activate_via_cli(type, path, opts)
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end
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end
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end
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···
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def socket_available?(socket_path \\ @default_socket_path) do
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File.exists?(socket_path)
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end
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@doc """
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Check if the username tag matches the current user.
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Returns `true` if a username tag exists and matches `System.get_env("USER")`.
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Returns `false` if no username tag found or it doesn't match.
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"""
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def username_matches_current_user?(tags) when is_list(tags) do
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current_user = System.get_env("USER")
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case Enum.find(tags, &(&1.key == "username")) do
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%{value: ^current_user} -> true
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_ -> false
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end
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end
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def username_matches_current_user?(_tags), do: false
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# Private functions - Socket communication
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+114
-1
apps/sower_client/test/sower_client/activator_test.exs
+114
-1
apps/sower_client/test/sower_client/activator_test.exs
···
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end
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test "falls back to CLI when socket not available" do
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# Ensure the executables don't exist in PATH
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original_path = System.get_env("PATH")
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System.put_env("PATH", "/nonexistent")
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···
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assert {:error, :cmd_not_found} = result
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end)
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end
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+
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test "home-manager with matching username bypasses socket" do
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{socket_path, server_pid} =
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start_mock_server(fn _request_line, _client_socket ->
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# This should not be called - we're testing CLI bypass
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flunk("Socket should not be contacted for same-user home-manager")
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end)
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original_user = System.get_env("USER")
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System.put_env("USER", "alice")
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original_path = System.get_env("PATH")
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System.put_env("PATH", "/nonexistent")
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on_exit(fn ->
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System.put_env("USER", original_user || "")
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System.put_env("PATH", original_path)
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stop_mock_server(server_pid)
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File.rm_rf!(Path.dirname(socket_path))
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end)
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tags = [%{key: "username", value: "alice"}]
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capture_log(fn ->
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result =
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Activator.activate("home-manager", "/nix/store/xyz",
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socket_path: socket_path,
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tags: tags
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)
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assert {:error, :cmd_not_found} = result
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end)
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end
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test "home-manager with mismatched username fails without socket" do
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original_user = System.get_env("USER")
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System.put_env("USER", "alice")
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on_exit(fn -> System.put_env("USER", original_user || "") end)
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tags = [%{key: "username", value: "bob"}]
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capture_log(fn ->
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result =
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Activator.activate("home-manager", "/nix/store/xyz",
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socket_path: "/nonexistent/socket",
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tags: tags
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)
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assert {:error, :username_mismatch} = result
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end)
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end
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test "NixOS activation still uses socket when available" do
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{socket_path, server_pid} =
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start_mock_server(fn request_line, client_socket ->
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request = Jason.decode!(request_line)
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assert request["type"] == "nixos"
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send_response(client_socket, %{id: request["id"], type: "complete", exit_code: 0})
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end)
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on_exit(fn ->
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stop_mock_server(server_pid)
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File.rm_rf!(Path.dirname(socket_path))
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end)
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assert {:ok, []} =
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Activator.activate("nixos", "/nix/store/xyz", socket_path: socket_path)
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end
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+
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test "home-manager without username tag returns appropriate error" do
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original_user = System.get_env("USER")
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System.put_env("USER", "alice")
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+
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on_exit(fn -> System.put_env("USER", original_user || "") end)
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+
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capture_log(fn ->
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result =
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Activator.activate("home-manager", "/nix/store/xyz",
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socket_path: "/nonexistent/socket",
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tags: []
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)
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assert {:error, :missing_username_tag} = result
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end)
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end
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end
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describe "reboot/1" do
···
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assert {:error, :cmd_not_found} = result
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end)
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end
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end
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+
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describe "username_matches_current_user?/1" do
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test "returns true when username tag matches current user" do
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original_user = System.get_env("USER")
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System.put_env("USER", "alice")
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+
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on_exit(fn -> System.put_env("USER", original_user || "") end)
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tags = [%{key: "username", value: "alice"}]
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assert Activator.username_matches_current_user?(tags)
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end
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test "returns false when username tag doesn't match current user" do
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original_user = System.get_env("USER")
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System.put_env("USER", "alice")
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on_exit(fn -> System.put_env("USER", original_user || "") end)
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tags = [%{key: "username", value: "bob"}]
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refute Activator.username_matches_current_user?(tags)
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end
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test "returns false when no username tag present" do
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refute Activator.username_matches_current_user?([])
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refute Activator.username_matches_current_user?([%{key: "other", value: "test"}])
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end
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end
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